Rather than buying separate flights from one destination to another, a flexible and sometimes cheaper way of international travel is via Round the world (RTW) tickets. A round the world ticket is a plane ticket allowing you to fly around the world, usually over a period of up to a year and with between three and twenty stops at different airports. Computerised e-tickets seem to have reduced this to a maximum of 16 segments.

Round the world tickets usually cost far less than the sum of the one-way tickets between each set of individual stops. (One-way tickets are generally a poor value compared to round-trip tickets, and also may be viewed with suspicion by security or immigration personnel.) These tickets are usually slightly more expensive than a return ticket between destinations on opposite sides of the world (London and Sydney for example), but if you were planning two or more stops then you may find that a round the world ticket is the cheapest option, and allows you at least a side trip. Many travelers plan entire holidays using a round the world itinerary.

Because no individual airlines offer truly global service, round the world tickets are often associated with an airline alliance and allow you to travel with any airline that is part of the alliance. Note that the specialist travel agents mentioned below can book these flights and provide alternative deals.

The major alliance RTW offerings available worldwide are:

Star Alliance Round the World Fare, [1]. With 27 airlines, covering over 192 countries and 1,316 destinations, this is the champion for sheer number of destinations and easy routing. The pass is available in 29,000, 34,000 and 39,000 mile versions — in either Economy, Business or First Class — each with up to 15 stopovers. There is also a special "Starlite" Economy-only fare for 26,000 miles, but this is limited to a maximum of 5 stopovers. As in most of these fares, Star's rules require passengers start and end in the same country, but not necessarily in the same city. Some backtracking is allowed, though not over oceans. Backtracking, surface sectors, and transits/connections all count against the mileage total. As for where in the world you can go? Almost anywhere: in addition to the usual suspects, Star has a near-monopoly stranglehold on some regions including Micronesia and the South Pacific. South & Central America are also covered now, after Brazil's TAM joined Star Alliance on May 13th 2010. Panama's COPA and multi-national TACA (with hubs in El Salvador, Costa Rica and Peru) are scheduled to come aboard at some point. A black spot includes domestic flights within Australia, although there are plenty of international flights to the major cities.

The unique OneWorld Explorer is based on the number of continents visited (from three to six) and has no maximum mileage limit. Up to 16 segments, as opposed to stopovers, can be included — in any class of service. However, because of that flight (or "segment") ceiling, this fare can be more limiting than it first seems. (Also, only two stopovers are permitted in the continent of origin.) On the other hand, routings that require major backtracking (ie: from Europe to Africa) are more easily accommodated here, than they are in mile-centric fares. Travelers are free to change the dates on their ticket at no extra charge.

Global Explorer is Oneworld's more conventional, mileage-based RTW (26,000, 29,000 or 39,000 in Economy class only; 34,000 in Economy, Business or First class). While the OneWorld Explorer is limited to the full members of Oneworld, several non-Oneworld alliance airlines (including Aer Lingus, Air Pacific, Alaska Airlines and its affiliate Horizon Air, Gulf Air and S7 Airlines. Qantas code share flights operated by Air Tahiti Nui, Jetstar, South African Airways and Vietnam Airlines can also be used.) can be used with the Global Explorer. For this reason, travel to certain regions -- e.g. many South Pacific islands -- is easier with Global Explorer than with Oneworld Explorer. Surface segment rules are particularly rigid and constraining on the Global Explorer, and the 16-segment restriction applies. As with the Star Alliance mileage-based RTWs, all miles are counted, including surface segments. Each surface segment also consumes one of the 16 permitted ticket segments.

Regions with good coverage: North America, South America (including the Galapagos and Easter Island), the Caribbean, Easter Island, Europe, Middle East, Eastern Asia, parts of the South Pacific (Global Explorer), Australia, India and Russia.

Skyteam Round the World, [3]. This 20-airline alliance runs a distant third, and has lost even more ground after Continental defected to Star through United. COPA of Panama has also followed. Regardless, SkyTeam has singular strengths in Russia and central Africa, and the addition of China Southern Airlines (2007), China Eastern Airlines (2011) and China Airlines (2011) provides vast new options in China, Taiwan and around some of Asia's more interesting nooks. Mileage and rules are similar to Star Alliance's RTW. With the addition of Vietnam Airlines in 2010, coverage of Vietnam and surrounding countries of Cambodia and Laos is very good.

Weak Areas: South America, the Middle East, India, Australia, Micronesia and the South Pacific (the latter may change with the addition of Aerolíneas Argentinas in 2012).

The Great Escapade, [4] 29,000 miles and unlimited stops throughout the Virgin Atlantic, Air New Zealand and Singapore Airlines and SilkAir network — great coverage in South-East Asia and the Pacific, but spotty elsewhere. Backtracking allowed. The maximum number of stops within mileage is about 10, eg. London - Delhi - Bangkok - Bali - Australia Stop - New Zealand Stop - Fiji or Rarotonga - Los Angeles - London. Prices are good value and start from £1025 including tax. For some reason however, this ticket requires that travel must be commenced in either London UK or Manchester UK which effectively prevents North American purchasers from using a westward routing.

Regions with good coverage: South Pacific, South-East Asia

Four Corners. Singapore Airlines, Lufthansa, Air New Zealand, Virgin Atlantic. Similar to Great Escapade, but with better coverage in Europe and worse coverage in South-East Asia.

Regions with good coverage: South Pacific, Europe

Discovery tickets. Qantas, Cathay Pacific, Air Pacific, British Airways, and most Qantas codeshares. This is probably the 2nd biggest selling RTW out of the UK, allowing 29000 miles and 6 stops. However an extra 1500 miles can be bought for £100, or 3000 miles for £200. This choice is a lot cheaper than the Global Explorer and the One World, with similar routings, including Africa and South America, and from £765 plus tax.

Regions with good coverage: Australia, Asia.

World Walkabout Plus tickets. Qantas, Cathay Pacific, Air Pacific, British Airways, and most Qantas codeshares. This is the biggest selling RTW out of the UK, allowing 29000 miles and 7 stops - 4 can be in Australia including the point of turnaround - within a wide variety of itineraries using the joint Qantas and British Airways route networks. Basically you're allowed 7 stops (including up to 3 in Australia and 3 in New Zealand) and you must travel out and back via Australasia sticking roughly to the routings of the airlines involved.

Air New Zealand comes close to offering a full RTW flights, but has to codeshare between Singapore or Hong Kong to London.

Singapore Airlines also has a RTW valid only on their own flights, but travellers have to make their own way between the East and West Coasts of North America.

KLM Passport to the World offers between 3 and 10 stops.

Virgin Round the World ticket[5] with Virgin Atlantic and V Australia.

Quite a few more sell two-airline RTWs, with some examples being:

Air New Zealand and Virgin Atlantic 4 Stop Plus.. This is probably the cheapest net fare RTW out of the UK (From 639 plus tax), allowing 4 stops plus extras for a fee.

1 stop allowed in the Far East (Hong Kong, Tokyo or Shanghai)

1 Stop in the USA (San Francisco or Los Angeles, however new for 2009 you can now fly into Miami, New York, Boston, Washington, San Francisco or LA from the UK on Virgin.

Pacific Island stopovers (Rarotonga, Tonga, Western Samoa) allowed for an additional fare of £110 per stop on the outbound journey or £220 per stop on the return trip.

Unusually if you pay an Australia fare, then you can have the option of visiting both Australia and New Zealand. However if you only want to visit Sydney, Australia you can pay the lower New Zealand Fare and still visit the two countries. e.g. London - Hong Kong - Sydney - Auckland - San Francisco-London is an Auckland fare.

Surface sectors allowed, eg. you can fly into Hong Kong and out from Shanghai as long as you provide your own transportation between the two.

Return dates can be changed for £9. Maximum Stay: 12 months.

Regions with good coverage: United Kingdom, Hong Kong, Australia, New Zealand, USA

Air New Zealand and one of Cathay Pacific, El Al, Gulf Air, Lufthansa, KLM, Royal Brunei

United and one of Cathay Pacific, Emirates, Saudi Arabian, South African

These can be cheaper than full alliance RTWs, but your choice of routing is severely restricted and tickets can only be purchased in certain locations, not across the network. Inquire with the issuing airline for details.

If you want to do a long, circular itinerary that isn't quite all the way around the world, there are a number of interesting alternative options also available:

Oneworld Circle Trip Explorer, [7]. A do-it-yourself kind of fare where you pay for the number of continents visited (minimum three, maximum four). Note that a stop in Africa is obligatory.

Oneworld Circle Pacific, [8]. 22,000 to 29,000 miles around the Pacific Rim, covering Asia, Oceania, North America and South America.

Oneworld Circle Atlantic, [9]. 17,000 to 25,000 miles around the Atlantic. Travel is between cities in USA, Canada, Mexico, South America and Europe/Middle East.

Oneworld Circle Asia & South West Pacific, [10]. 13,000 to 17,000 miles around Asia and Australasia.

Star Alliance Circle Pacific, [11]. Allows you to loop around the Pacific Rim, for a total trip of 22,000-26,000 miles. Excellent coverage in Asia, but in North America you can only visit Los Angeles, San Francisco, Seattle, Honolulu and Vancouver.

Star Alliance Circle Asia, [12]. 15,000 or 18,000 miles all around Asia. Your journey must cover all three regions, defined as "South-West Pacific", "North Asia" and "South-East Asia."

Circle Atlantic and Circle Pacific fares are also offered by some individual airlines, such as United and Malaysia Airlines.

If you book an intercontinental round trip flight on an alliance airline you are eligible for passes that give discount flights in the destination continent.

It is possible to put together a round-the-world route by combining one-way tickets on various airlines. This is more flexible than restricting yourself to what an alliance offers and, if you get good discounts on some hops, pricing can be competitive. The only practical way to do this — since it requires both knowledge and contacts — is to go to a travel agent who specializes in round-the-world itineraries. These can be found in major cities that are transit hubs — San Francisco, (AirTreks) London, (STA Travel) or (roundtheworldflights.com) or (Travel Nation), Bangkok, (Visa First), Dublin, etc. — and many of them also provide services online, such as (BootsnAll). or (ticketsroundtheworld.com). In the Nordic countries and the Netherlands(KILROY travels) does the job. You could also save a lof by hiring a professional travel hacker at Flystein.

Around the World Tours- Based in Europe, with consultants in Australia and USA, Around the World Tours is a team of RTW experts that can help the traveler save time, define the appropriate itinerary, find the best RTW flights and the most direct and reliable travel suppliers all around the world. Around the World Tours builds tailor-made RTW tours, Classic, Themed & Branded, and offers a selection of the best RTW packages on the market. Their service is for free.

The booking process can take a few days or weeks depending on how fast you wish to expedite the process. These agents will get parts of your ticket issued by their contacts in other countries or in-house contracts. This can save a lot of money over the airlines.

It's now possible to fly entirely around the world on discount airlines (low cost carriers), although the routings possible are restricted. Your tickets will, in general, be completely inflexible, with steep fees for making any changes (if allowed at all), but for the frugal traveler this is still the cheapest option. See Discount airlines for some options and sample itineraries.

Over the last 18 months RTWs have been restricted to 16 sectors in a PNR (Passenger Name Record). This includes flight and surface sectors. The reasons it was introduced by IATA were vague but involved the general introduction of e tickets (electronic tickets)and the airlines inability to read PNRs over 16 sectors. This does affect all RTWs and is worth bearing in mind.

A strict mileage limit. Typical limits range from 26 000 to 40 000 miles, depending on the ticket price. "Land legs" -- traveling between two airports without using the ticket -- will typically count towards the mileage limit, so you cannot have a longer trip by doing this. (Note the Oneworld Explorer has no mileage limit but is based on the number of continents included.)

A time limit in which to make the journey. This is usually the same as an open-ended return ticket, that is, 12 months after your date of departure.

A minimum number of stops (including your return home): often three.

A maximum number of stops: five and up, depending on the ticket price.

Returning to your departure point (or at least the country of origin) on the last leg of the trip.

Traveling in one direction (east or west) only, usually interpreted per continent (ie. you can't cross the Atlantic or Pacific more than once).

A fixed series of stops determined at the time the ticket is booked (date alterations are usually allowed). Changes in itinerary (routing, stopover points) may require that tickets be re-issued, usually at a cost of USD 100 - 150 plus additional taxes and fuel surcharges if applicable.

Note that a RTW "stop" is usually defined as spending more than 24 hours in a place. Changing planes in transit does not count, and you can use this to squeeze in additional brief day visits. Depending on ticketing rules, in a few places with limited flights, it may even be possible to "transit" for several days while waiting for the next flight out.

The probably easiest and, at the same time, most exciting way to plan and book your Round the World trip is Star Alliance's Book and Fly tool: Start your journey here!

Some ways to get the maximum value from your ticket are:

Use a mileage calculator to maximize your route. The Great Circle Mapper [15] is an excellent tool, but be sure to set the display to "mi" (miles), not "nm" (nautical miles).

Use direct flights whenever possible. Be flexible with dates; routes off the beaten track are often not flown daily.

Start your trip from a low-cost country. RTW pricing depends on where you issue the ticket, so you can achieve significant savings by starting from places like Bulgaria, Sri Lanka or Thailand. As an example, in April 2005, a Star Alliance RTW3 in First would have cost you $16,509 if purchased in the United Kingdom, but only $7,929 (a savings of 52%) if purchased in Tonga.

The famous Canadian exception means that RTWs sold in Canada cost the same as at the point where the trip begins. For example, that means you can buy a ticket in Canada for an RTW beginning in Thailand and pay the much cheaper Thai price. Of course, you have to get to Thailand in order to start the RTW but the extra ticket you need will probably cost less than the difference in the RTW fares; in other words, you still save money.

The United States is one of the more expensive places to begin a RTW trip (due to a combination of geography and lack of demand for such tickets compared to other countries). If Europe is on your itinerary, it is often up to a thousand US dollars cheaper to buy a ticket through a UK travel agent starting in London. You can do this via email and over the phone, and purchase a cheap one-way ticket to Europe to begin your travels. To return, just make sure your routing goes through the US at the end and don't take the last leg back to London. (i.e. you must fly eastward only.)

Start your trip in low season; in some cases this lowers the overall fare drastically.

Consider flying business class (or, for a real splurge, first). Yes, you'll pay about twice as much for the ticket — but business class usually costs 4-7x more than economy, so it's a comparative steal, and it makes all that sitting around in planes so much more tolerable. Also, it gets a larger baggage allowance; for some travellers it may be better to pay once for business class than to get hit for excess baggage on several legs of the trip.

Join a frequent flyer program before you fly. With all the miles you rack up from your RTW, you'll earn enough to make another trip for free when you get back.

Watch out for taxes and surcharges. These are not included in the base cost of the RTW, but can easily add up to hundreds of dollars, and some countries (e.g., much of Europe) are much more expensive than others (e.g., most of Asia). Also, don't forget the cost of visas, if required.

When choosing your destinations, consider whether an RTW is the best solution for visiting them. As a very rough rule of thumb for gauging costs, assuming a 29,000-mile ticket for $3000, one mile of an Economy RTW costs (on average) around $0.10.

Consider some offbeat, once-in-a-lifetime destinations. For example, regular flights to Svalbard, Easter Island, or much of Oceania and Africa are horrifically expensive, but virtually free (only miles needed) when using a RTW ticket. Note that for routing reasons, places like Greenland are still inaccessible (it's considered North America, but you can only fly in or out from Europe.)

Consider taking non-alliance airlines for routes less traveled. As an example, suppose you'd like to fly from Dubai to Athens. You'd be hard-pressed to find a good route with most RTW tickets, as neither Emirates nor Olympic participate in the major programs, and would have to detour through a hub like Frankfurt, racking up over 4000 miles (~$400). On the other hand, direct flights on non-allied airlines cost as little as $196.

Consider taking discount airlines for return excursions. For example, Bangkok-Singapore return would set you back 2000 miles (~$200), but on this heavily competed sector full-service carriers regularly offer fares under $100 and low-cost carriers promotions can be under $10.

Some tips to consider if you need to squeeze in a few more miles:

Use Metropolitan Area Airport Codes instead of airport-specific ones. For London, LON covers Heathrow, Gatwick, Stansted and London City, while for Tokyo, TYO covers both Narita and Haneda. SIN-TYO clocks in at 3294 mi while SIN-NRT is 3324 m — a difference of 30 miles.

Stops on the same flight don't count. If ticketed so that Tromsø doesn't show on the ticket, a flight from Oslo to Longyearbyen is 1255 mi, not 1292 mi, even though there is a stop at Tromsø. (Note that the Star Alliance mileage calculator does not handle this correctly.)

You (usually) don't need to start and end your journey in the same city, as long as you end up in the same country. For example, starting in New York City and ending in Los Angeles, then using a cheap, separately purchased one-way ticket to get back to New York (e.g. JetBlue, Southwest, ATA) would free up a few thousand miles. Note to Americans: at least according to Star Alliance, Guam and Puerto Rico are different countries.

Destinations in the tropics tend to use up more mileage, as this is where the earth is at its widest, and international airports are often few and far between. Try to find an alternate destination a little further from the equator, and more in line with the previous and subsequent airport.

If you want to fly around the world completely in the Southern Hemisphere, the choice of flights and destinations is limited due to the lack of transoceanic routes. No airline alliance presently covers all three ocean crossings in the Southern Hemisphere. However, Star Alliance covers everything except the eastern South Pacific from Santiago de Chile to Tahiti, which is a LAN Oneworld flight. This flight not the only option if you want to skip the South Pacific and the west coast of South America. (see below)

If you're starting in North America, Air New Zealand (Star Alliance) has flights from Los Angeles to Tahiti (code share), the Cook Islands, Samoa/Tonga, and Auckland. For Star Alliance members in USA/Canada, getting in and out via Samoa or Tahiti may be the best route.

Air Mauritius has flights from Australia to Mauritius, and from there to Johannesburg, Cape Town, Durban, Nairobi and other African cities. (This is the most direct option if you want to stop in Madagascar or Kenya en route.) (unaffiliated, but some codeshares with Star Alliance member South African Airways)

You can also transit through Singapore (Star Alliance) or Malaysia (Oneworld 2012) to Johannesburg, but this is slightly north of the equator.

Even for alliancewide RTWs, the ticket will be issued by one airline. If you need to change a flight leg, it is best to first contact the carrier you will be flying with, and if they can't help, then consult the issuing airline.

After your ticket has been issued, you are typically allowed to change the dates of your flights for free (except the first international leg), but changing the destinations will require a hefty reissuing fee (US$125 for Star Alliance). Flying the same route on another carrier covered by the pass may or may not be possible.

Two big warnings - Never just skip a flight on a RTW ticket or you may find that the seat reservations for your subsequent flights are automatically canceled without warning or notice. It is reported that Cathay Pacific will do this, regardless of whether the future flights are connections for the one that you missed or booked months in advance. If you leave it and try and reconfirm immediately after missing the flight, you stand a very good chance of being put on a wait list because your seats have already been resold. Always call to cancel or change the flight in advance or phone immediately to reconfirm all flights, regardless of whether the airlines require reconfirmation normally.

Yellow fever vaccinations: Some countries require this even though there are no cases in your home country, the places you've just visited, and where you're headed to. Example: You've just visited Rio de Janeiro and are continuing on to Australia. They require vaccination for anyone who's been to Brazil within the past week, no matter what areas you've been to. Australian tourists who visit Brazil are aware of this, but someone else on a round-the-world holiday may never have heard of such a thing. If visiting countries wholely or partly located in the tropics, check vaccination requirements of every future destination in the world you plan on visiting, noting all previous tropical countries on your itinerary. In some cases, you may be able reverse your direction of travel to avoid needing any vaccinations. Of course, if you're visiting an endemic area, you should inquire about vaccinations months before leaving home -- even if not legally required.

This is a usable article. It touches on all the major areas of the topic. An adventurous person could use this article, but please plunge forward and help it grow!